CODEWITHSUNDEEP
flutterdart
Luis Cardoza Bird
Luis Cardoza Bird

Reputation: 1482

Flutter firestore return Future<List<Data>> returns empty

I have a function that retrieve a List of data as a Future.

final CollectionReference _departmentHoursCollection =
  FirebaseFirestore.instance.collection('departmentsHours');

Future<List<DepartmentHour>> isUnfinishedGK(List<String> sites) async {
    sites.asMap().forEach((key, value) async {
      QuerySnapshot departmentsHoursSnapshot = await _departmentHoursCollection
          .where('siteName', isEqualTo: value)
          .where('justification', isEqualTo: 'working')
          .get();
      if (departmentsHoursSnapshot.docs.isNotEmpty) {
        departmentsHoursSnapshot.docs.asMap().forEach((key, value) async {
          var document = await value.reference.get();
          print(document.data());
          _temporal.add(DepartmentHour.fromMap(document.data()));
        });
      }
    });
    print("size: ${_temporal.length}");
    return _temporal;
  }

however when i print size at the end, it keeps showing:

I/flutter (20592): size: 0

But the data is being fetched and added to the variable: _temporal:

I/flutter (20592): {globalTime: 24304, endHour: 06:00, startedTime: Timestamp(seconds=1602329908, nanoseconds=453000000), departmentHourDetails: [{globalTime: 24300, endJobTime: Timestamp(seconds=1602354212, nanoseconds=456000000), department: Grind Room, startJobTime: Timestamp(seconds=1602329911, nanoseconds=766000000)}, {globalTime: 24299, endJobTime: Timestamp(seconds=1602354212, nanoseconds=456000000), department: Main Production, startJobTime: Timestamp(seconds=1602329913, nanoseconds=94000000)}], startHour: 22:00, scheduleDate: Timestamp(seconds=1602306000, nanoseconds=0), finishedTime: Timestamp(seconds=1602329908, nanoseconds=453000000), siteName: SMD, justification: working}

anyone knows how to return the List with the fetched data instead of returning a [].

Upvotes: 0

Views: 145

Answers (1)

Try
Try

Reputation: 3469

To solve the problem you can use Future.forEach(), that waits for each Future to be completed before moving to the next element, as you can see here.

Example:

Future<List<String>> myFuture(List<String> names) async {
  List<String> newNames = [];

  await Future.forEach(names, (name) async {
    await Future.delayed(Duration(seconds: 2), () {
      newNames.add(name);
    });
  });

  return newNames;
}

Upvotes: 1

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